The present invention relates generally to a vehicle drive control apparatus and method, and more particularly to a vehicle drive control apparatus and method for speed shift control for an automotive vehicle operable in at least a fixed speed ratio mode in which a speed ratio of an output to an input is fixed and at least a variable speed ratio mode in which the speed ratio is allowed to vary.
Japanese Published Patent Application No. 2004-150627 (henceforth referred to as “JP2004-150627”) shows a hybrid drive system for an automotive vehicle that has six rotating elements in a below-described speed relationship diagram and interconnects an input from an engine, an output to drive wheels, a first motor generator, and a second motor generator. This hybrid drive system is configured to establish a continuously variable speed ratio mode and a fixed speed ratio mode. In the continuously variable speed ratio mode, the speed ratio of an output to an input is controlled to vary continuously, while in the fixed speed ratio mode the speed ratio is controlled to be fixed by holding stationary one of the rotating elements by means of a brake. These modes are each selected in accordance with a running state of the vehicle.